Capitol Federal Savings Bank is issuing 8,000 new debit cards to customers whose account numbers and expiration dates were stolen recently from a national merchant’s database.

The move, disclosed earlier this month to Cap Fed’s victims in a letter, will cost the Topeka-based bank about $11,000, said Frank Wright, the bank’s senior vice president for electronic banking.

“It’s the cost of doing business,” said Wright, who lives in Lawrence. “It’s cheaper to do that than to have a bunch of fraudulent transactions.”

Wright said there already had been “dozens” of suspect attempts to use the Visa account numbers that had been stolen from the unidentified merchant; computer programs flagged the attempts and did not authorize payments.

Cap Fed be-comes aware of “two or three” such thefts a year, he said, but the latest case is by far the biggest. Previous cases have involved dozens or several hundred accounts.

Affected customers should have their new cards by the end of this week, he said.